Differential gear for motor-vehicles.



G. J. PITTMAN. DIFFERENTIAL GEAR FORZMOTOR VEHICLES.

APPLICATION FILED MAY 11, I308.

Patented Oct 20, 1908.

c, x 1 KW UNITED STATES rAtrENT OFFICE.

CHARLES JOSEPH PITTMAX, ()l REDFERN, NEAR SYDNEY, NEW SOUTH WALES,AUSTRALIA, ASSIGNOR OF ONE-HALF TO FRANK IRELAND, O-F SYDNEY, NEW SOUTHWALES,

AUSTRALIA.

DIFFERENTIAL GEAR FOR MOTOR-VEHICLES.

Patented Oct. 20, 1908.

Application filed May 11, 1908. Serial No. 432,186

To all whom it may concern:

Be it known that I, CHARLES JOSEPH Irr'rarsx, a subject of the King ofGreat Britain,

invented certain new and useful Improveinentsin Differential Gears forMotor-Vehicles. of which the following is a specification.

This invention relates to improved gear for motor or self propelledvehicles for the purpose of automatically varying the relation of thedriving wheels to each other when describing a curve.

' The object is to provide simple inechan ismwhich will be much lessexpensive and more reliable than gears hitherto employed for thepurpose. mentioned.

My invention has special reference to motor vehicles ofthe side chaintransmission type in which power is conveyed to a transverse shaft, fromsprocket wheels on which it is transmitted by chains to sprockets on thedriving wheels. f

It consists in the means described whereby in negotiating a curve thetendency of the outside driving wheel to revolve more rapidly than 'theinside driving wheel-causes the outside sprocket on the transverse shaftto rotate freely forwardly (or rearwardly on reversing the motor) andthereby permits the outside driving wheel to revolve freely.

According to my invention in its preferred form 'the transverse ordriving shaft has loose thereon suitably notched or toothed wheels eachintegral with the sprocket wheel on the same side of said shaft. Adouble acting pawl is pivoted near to each of said notched wheels sothat one of its arms or detents may take. into one of the notchestherein on the forward and the other on the backward drive therebycoupling the said wheels to the shaft the transmission of power beingthrough one or other of the arms of said pawl. I may employ a two armedand a one armed pawl on opposite sides of. the same driving shaft butwhere the vehicle is of the non-reversing type the pawls have eachonearm or detent through which the power is transmitted on the forwarddrive.

Referring to the drawings herewith Figure 1 is a perspective view of theinvention a wheel to the driving wheels of a motor car. big. 2 is anenlarged perspective view vention. F igls. 3, 4, and 5 are diagrammaticviews showingthe pawls in different positions.

The same reference numerals indicate the same or like parts.

To the transverse driving shaft 10 are keyed two crank arms 11 to eachofwhich, is pivoted the double pawl 12. Each pawl is again fulcrum ed ona pin 13 which is screwed or otherwise secured -1nto a. disk 14 looseupon the shaft '10. The connection between the .pawl '12 and the'disk 14is sufliciently looseto permit these parts'to operate about theirrespective axes. The pawl has two armsor detents l5 and16 either ofwhich is capable of engaging with the toothed wheel or circular rack 17integral with the sprocket wheel 18. 19 represents the driving wheels.

When avehicle provided with my invention is running ahead the shaft 10through the cranks 11 operates the pawls 12 so that the detent 16 oneach side of the vehicle is in engagement with its toothed wheel 17 asshown in Fig. -1 the power from the driving shaft being transmittedtherethrough. On the direction of the vehicle being' reversed thedetents 15 engage the said toothed wheels as shown in Fig. \l'henhowever the vehicle is describing 'a curve the outside drivtransmittedthrough the inside pawl and its toothed wheelj When an opposite curve isbeing negotiated the opposite sprocket and driving wheel operate in thesame-manner. Immediately a straight. course is taken the detent 16engages with the teeth on the wheel 17 when both sprockets on thedriving sliaft are coupled thereto and rotate at a uniform rate. Botharms of each pawl may be raised clear of their respective toot-liedwheels, such as in descending a hill, thereby allowing both drivingwheels to run freely.

Should it be necessary I may provide suitable springs to engage withthe. pawls in order to facilitate their action.

In applying-my invention to motor vehicles driven by a central chaintransmission ilustrative of the essential parts of my in-- or shaftingand toothed gearing on a divided 1. A differential gear for vehiclescomprising a driving shaft, an arm fixed to turn therewith, a partloosely balanced on said shaft, a notched wheel also loosely mounted onsaid shaft, and a pawl pivotally mounted on said arm and fulcrumed 011said part, said pawl having an arm' adapted to be engaged and disengagedrelatively to the notched wheel by a relative rotation of said arm andart. P 2. A differential gear for motor vehicles comprising a drivingshaft, an arm fixed to turn therewith, a dlsk loosely balanced on saidshaft, a notched wheel also loosely mounted on the driving shaft, and apawl pivotally connected to said arm and fulcramed on said disk, thepawl having a pair of reversely arranged arms either of which is adaptedto be engaged and disengaged relatively to the notched wheel by arelative rotation of said arm and disk.

3. A difi'erential gear for motor vehicles comprising a driving shaft,an arm fixed to rotate therewith, a notched wheel loosely mounted on thedrivingshaft, a disk also loosely mounted on the driving shaft at oneside of said arm, and a pawl pivotally connesses.

CHARLES JOSEPH PITTMAN.

Witnesses:

CHARLES EDWARD GRAHAM, HENRY \VA'rcHoRNE CLARKE.

